Dark-acclimation of the Chloroplast in Koliella antarctica Exposed to a Simulated Austral Night Condition

Baldisserotto, Costanza; Ferroni, Lorenzo; Andreoli, Carlo; Bonora, A.; Pancaldi, Simonetta

doi:10.1657/1523-0430(2005)037[0146:dotcik]2.0.co;2

Cited by 27 publications

(53 citation statements)

References 46 publications

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“…This idea was convincingly supported by demonstration that this microalga could grow equally well in both saline and freshwater media (Zanetti et al 2001, Baldisserotto et al 2005, Ferroni et al 2007. Moreover, at very low salinities, K. antarctica showed the typical spindleshaped cell morphology of the genus, while at higher salt concentrations, the algal cells changed their shape becoming curled or even sigmoid (Andreoli et al 1998, Zanetti et al 2001.…”

Section: Methodsmentioning

confidence: 87%

“…Cd is present in the Ross Sea of Antarctica at concentrations much lower than those of other heavy metals such as Ni, Pb, Cu and Zn, in both surface sediments (mean 0.35 ppm) and water column (<1 nmol l -1 ) (Bargagli 2005). The lowest values of Cd occur in water after ice melting, due to Cd uptake or scavenging by bloomed phytoplanktonic populations (Scarponi et al 2000).…”

Section: Introductionmentioning

confidence: 99%

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Responses of the Antarctic microalga Koliella antarctica (Trebouxiophyceae, Chlorophyta) to cadmium contamination

Rocca¹,

Andreoli²,

Giacometti³

et al. 2009

Photosynt.

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Ultrastructural and physiological effects of exposure to 1 ppm and 5 ppm of cadmium (Cd) on cultured cells of Koliella antarctica, a green microalga from Antarctica, were investigated. The amount of Cd in the alga rose with the increase of the metal concentration in the growth medium and most Cd remained outside the cells, bound to the components of the cell walls. The increase of Cd in the microalga was concomitant with the decrease of other elements, mainly calcium (Ca). Exposure to 1 ppm Cd slowed culture growth by inhibiting cell division and also caused the development of some misshapen cells with chloroplast showing disordered thylakoids. However, this concentration did not substantially affect the chlorophyll (Chl) content or photosystem (PS) activity. At 5 ppm, Cd cell growth suddenly stopped and some cells lysed. After a week of Cd contamination, the cells were enlarged and severely damaged. The chloroplasts showed great ultrastructural alterations and a reduced Chl content. Cd exposure negatively affected PSII, whose activity was almost completely lost after four days.

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Section: Methodsmentioning

confidence: 87%

Section: Introductionmentioning

confidence: 99%

Responses of the Antarctic microalga Koliella antarctica (Trebouxiophyceae, Chlorophyta) to cadmium contamination

Rocca¹,

Andreoli²,

Giacometti³

et al. 2009

Photosynt.

Self Cite

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“…Consequently, a higher metabolic rate caused by an increase of temperature, as predicted in global warming scenarios, can lead to a more rapid catabolism of stored energy products and hence possibly to shorter dark survival times (McMinn and Martin 2013). This could be followed by the utilization of other potential energy sources, such as the degradation of organelles like chloroplasts (Baldisserotto et al 2005;Karsten et al 2012) or the switch to a heterotrophic lifestyle, i.e. uptake of bioavailable sugars and amino acids from the environment (Hellebust and Lewin 1977;Palmisano and Sullivan 1982;Tuchman et al 2006).…”

Section: The Lipids Metabolism Under Darknessmentioning

confidence: 99%

Effects of prolonged darkness and temperature on the lipid metabolism in the benthic diatom Navicula perminuta from the Arctic Adventfjorden, Svalbard

et al. 2017

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which could consequently lead to a depletion of this energy reserves before the end of the polar night. On the other hand, the membrane building phospho-and glycolipids remained unchanged during the 8 weeks darkness, indicating still intact thylakoid membranes. These results explain the shorter survival times of polar diatoms with increasing water temperatures during prolonged dark periods. Abstract The Arctic represents an extreme habitat for phototrophic algae due to long periods of darkness caused by the polar night (~4 months darkness). Benthic diatoms, which dominate microphytobenthic communities in shallow water regions, can survive this dark period, but the underlying physiological and biochemical mechanisms are not well understood. One of the potential mechanisms for long-term dark survival is the utilisation of stored energy products in combination with a reduced basic metabolism. In recent years, water temperatures in the Arctic increased due to an ongoing global warming. Higher temperatures could enhance the cellular energy requirements for the maintenance metabolism during darkness and, therefore, accelerate the consumption of lipid reserves. In this study, we investigated the macromolecular ratios and the lipid content and composition of Navicula cf. perminuta Grunow, an Arctic benthic diatom isolated from the microphytobenthos of Adventfjorden (Svalbard, Norway), over a dark period of 8 weeks at two different temperatures (0 and 7 °C). The results demonstrate that N. perminuta uses the stored lipid compound triacylglycerol (TAG) during prolonged dark periods, but also the pool of free fatty acids (FFA). Under the enhanced temperature of 7 °C, the lipid resources were used significantly faster than at 0 °C, Keywords

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“…Interestingly, K. antarctica shows elevated respiratory oxygen consumption rates, which suggests that the alga obtains through respiration a large quantity of metabolic energy to power cellular reactions at low temperatures (Vona et al, 2004). An enhanced dissipation of excess light energy as heat in the thylakoid membranes has also been proposed to favour metabolic activities (Giacometti et al, 2001;Baldisserotto et al, 2005a). Thus, growth under cold conditions appears to be linked to an intrinsically high capacity of cell structures to operate at the low temperatures that characterize the Antarctic sea (Vona et al, 2004;Baldisserotto et al, 2005a;Lenucci et al, 2006).…”

Section: Introductionmentioning

confidence: 99%

“…An enhanced dissipation of excess light energy as heat in the thylakoid membranes has also been proposed to favour metabolic activities (Giacometti et al, 2001;Baldisserotto et al, 2005a). Thus, growth under cold conditions appears to be linked to an intrinsically high capacity of cell structures to operate at the low temperatures that characterize the Antarctic sea (Vona et al, 2004;Baldisserotto et al, 2005a;Lenucci et al, 2006). Polar marine algae are not only exposed to low temperatures, but also to extremely variable light conditions, including complete darkness for long periods in winter, especially if the ice is covered with snow (Lu¨der et al, 2002).…”

Section: Introductionmentioning

confidence: 99%

Acclimation to darkness in the marine chlorophyteKoliella antarcticacultured under low salinity: hypotheses on its origin in the polar environment

Ferroni

Baldisserotto

Zennaro

et al. 2007

European Journal of Phycology

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2007) Acclimation to darkness in the marine chlorophyte Koliella antarctica cultured under low salinity: hypotheses on its origin in the polar environment, European Journal of Phycology, 42:1, 91-104, In order to obtain new insights on the origin and physiology of the marine chlorophyte Koliella antarctica, the response of the microalga was studied at a salinity of 0.2 in the light and during a 60-day dark period. In light conditions, the alga grows and maintains a functional cell organization. In darkness, the chloroplast-to-chromoplast transition, previously described during dark-acclimation in K. antarctica under a salinity of 34 was only partially triggered; thylakoid lamellae became re-organized into short bundles, but storage substructures were almost completely missing. Microspectrofluorometry, pigment analyses, and morphological observations revealed dark-induced degradation of photosystem II (PSII) with relative stability in the lightharvesting complex (LHCII). Chromatin condensation, mitochondrion fragmentation and material digestion in vacuoles were similar to morphological hallmarks of programmed cell death (PCD), but only 30% of cells underwent cell death and, at the end of the experiment, only 1-2% of cells were TUNEL-positive. Rapid recovery in culture growth after exposure to light showed that the changes apparent in the rest of cells were reversible. Taking into account the response of the plastid and assuming an adaptive benefit of PCD, our results are consistent with the hypothesis that K. antarctica evolved from an Antarctic freshwater ancestor.

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Dark-acclimation of the Chloroplast in Koliella antarctica Exposed to a Simulated Austral Night Condition

Abstract: BioOne Complete (complete.BioOne.org) is a full-text database of 200 subscribed and open-access titles in the biological, ecological, and environmental sciences published by nonprofit societies, associations, museums, institutions, and presses.

Cited by 27 publications

References 46 publications

Responses of the Antarctic microalga Koliella antarctica (Trebouxiophyceae, Chlorophyta) to cadmium contamination

Responses of the Antarctic microalga Koliella antarctica (Trebouxiophyceae, Chlorophyta) to cadmium contamination

Effects of prolonged darkness and temperature on the lipid metabolism in the benthic diatom Navicula perminuta from the Arctic Adventfjorden, Svalbard

Acclimation to darkness in the marine chlorophyteKoliella antarcticacultured under low salinity: hypotheses on its origin in the polar environment

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